The present invention relates to a device and process for manufacturing wheels for vehicles having a rim which is wreath-shaped in section around a cast wheel body, for example a central disc or dish-shaped body, with at least one mold wall delimiting the space to be filled with cast metal.
As wheels, axles and related support facilities are unsprung components in the vehicle, it is important both for safety and comfort when driving, that not only the material but also the connection between the rim and wheel is optimized.
One-piece cast wheels are known. However, because of the high costs for the mold, these wheels are very expensive to manufacture and furthermore exhibit a low degree of toughness. Also, high reject rates have to be accepted when making this kind of wheel.
For the foregoing reasons wheel rims and bodies are generally made separately and then joined. Known methods of joining rim and body are for example bolting, rivetting, welding or gluing. In many cases these methods do not provide the high level of mechanical properties expected of vehicle wheels and do not produce the dimensional accuracy and close fit needed for wheels for tubeless tires.
Diffusion layers are also used to join the rim to the wheel body. However, there is the risk of peeling off due to stresses which arise from shrinkage which stresses cannot be avoided completely. The relatively high cost involved in joining the parts is another disadvantage. Furthermore, with the moveable mold parts used for the rim well in present day foundry practice, there is the danger that these parts will lose their roundness when heated.
The present state of the art is the use of vehicle wheels made purely from semi-fabricated products. However this markedly limits the design possibilities.
It is therefore the principal object of the invention to develop a device and process whereby the foregoing disadvantages are completely or at least partly avoided and more particularly a device and process by means of which a good junction between wheel body and rim is achieved with a faultless structure, and at the same time achieving a simplification in the die, an increase in production rate and a reduction in die costs.